TY - JOUR
TI - A new approach for the analysis of the nanoparticles effects on Cu-water nanofluid mixed convection heat transfer and required power in a lid-driven cavity
AU - Nezhad Alireza Hossein
AU - Ardalan Mostafa Valizadeh
JN - Thermal Science
PY - 2016
VL - 20
IS - 2
SP - 405
EP - 414
PT - Article
AB - In this paper, a new approach is used for numerical analysis of the sole  effects of nanoparticles volume fraction of Cu-water nanofluid on laminar  mixed and natural convection heat transfer in a 2D cavity. Horizontal walls  are insulated and fixed, and vertical walls are maintained at constant  temperature. Vertical walls are considered for both fixed and moving  conditions. Some researchers have studied flow and heat transfer of nanofluid  in a lid-driven cavity, keeping fixed both Ri and Gr. They found that by the  increase of nanoparticles volume fraction, Nu number increases, then from  this result they concluded the total heat transfer increases from the walls.  It is shown that total heat transfer obtained from the Nu number by the  mentioned approach results from not only the nanoparticles volume fraction  increase but also temperature difference and walls velocity increases. Thus,  this approach is not appropriate to study the sole effects of nanoparticles  volume fractions on the mixed convection heat transfer. Using the new  approach, it is shown that in order to have specific heat transfer rate from  the walls, base fluid (water) needs less power for moving the wall than  cu-nanofluid. Therefore, the usage of Cu-water nanofluid is not recommended  to increase mixed convection heat transfer in a lid-driven cavity. Moreover,  using this new approach, it is shown that the increase of nanoparticles  volume fraction reduces natural convection heat transfer, which is  contradictory to the previous studies. Thus, its usage is not recommended for  this case as well.